Made double-tap zoom work in pinch virtual viewport mode. (Blink-side)

Source/web/WebViewImpl.cpp

Index: Source/web/WebViewImpl.cpp
diff --git a/Source/web/WebViewImpl.cpp b/Source/web/WebViewImpl.cpp
index 18d6939011cee586b8b011d77289778ce0b4768a..fe748490820a4b17a216c79649ef7b5088fd20e3 100644
--- a/Source/web/WebViewImpl.cpp
+++ b/Source/web/WebViewImpl.cpp
@@ -2889,7 +2889,10 @@ IntPoint WebViewImpl::clampOffsetAtScale(const IntPoint& offset, float scale)
     if (!view)
         return offset;
 
-    return view->clampOffsetAtScale(offset, scale);
+    if (!pinchVirtualViewportEnabled())
+        return view->clampOffsetAtScale(offset, scale);
+
+    return page()->frameHost().pinchViewport().clampDocumentOffsetAtScale(offset, scale);
 }
 
 bool WebViewImpl::pinchVirtualViewportEnabled() const
@@ -2938,6 +2941,19 @@ void WebViewImpl::setPageScaleFactor(float scaleFactor)
     deviceOrPageScaleFactorChanged();
 }
 
+void WebViewImpl::setPageScaleFactorFromImpl(float scaleFactor)
+{
+    ASSERT(page());
+    ASSERT(pinchVirtualViewportEnabled());
+
+    scaleFactor = clampPageScaleFactorToLimits(scaleFactor);
+    if (scaleFactor == pageScaleFactor())
+        return;
+
+    page()->frameHost().pinchViewport().setScaleWithoutClampingViewportOffset(scaleFactor);
+    deviceOrPageScaleFactorChanged();
+}
+
 void WebViewImpl::setMainFrameScrollOffset(const WebPoint& origin)
 {
     updateMainFrameScrollPosition(origin, false);
@@ -4146,8 +4162,10 @@ void WebViewImpl::applyViewportDeltas(const WebSize& scrollDelta, float pageScal
 
     if (pinchVirtualViewportEnabled()) {
         if (pageScaleDelta != 1) {
-            // When the virtual viewport is enabled, offsets are already set for us.
-            setPageScaleFactor(pageScaleFactor() * pageScaleDelta);
+            // When the virtual viewport is enabled, offsets are already set for us. Don't clamp

[aelias_OOO_until_Jul13, 2014/09/19 22:39:21]

We've so far always been able to avoid "don't clamp" methods and I'd prefer to
keep it that way; that kind of approach ends up having subtle assumptions about
the order that things are called in.  It's better to fix these by sending all
parameters that cross-clamp as arguments to one method.  Can we change the Blink
API to pass the scroll offsets for the inner and outer viewport to this method
as well?

+            // the viewport offset when setting page scale here, it will be clamped when the
+            // compositor sets the viewport offset immediately following this.
+            setPageScaleFactorFromImpl(pageScaleFactor() * pageScaleDelta);
             m_doubleTapZoomPending = false;
         }